Axial piston machine

ABSTRACT

A volumetric machine of the barrel or axial piston type includes pistons which rest on an oblique pivoting swash-plate which in turn drives the crank of a driving or driven shaft. The pivoting of the swash-plate is defined by a two-nappe frustrum of cone integral with the swash-plate and rolling, without sliding, on a stationary two-nappe frustrum of cone angularly integral with the frame of the machine. The two-nappe frustrums of cone have as their common generatrix the bisectrix of the obtuse angle defined by the axis of the machine and the axis of the swash-plate.

[451 Aug. 26, 1975 United States Patent Brille [54] AXIAL PSTON MACHINE FOREIGN PATENTS OR APPLICATIONS 251,630 7/1927 United Kingdom............ 123/58 BA 353,137 10/1937 123/58 BA 1,015,787 8/1952 Franceuu........................ 123/58 BA [76] Inventor: Maurice G. Brille, 27 rue Parmentier, Nanterre, France [22] Filed: July 24, 1973 Appl. No.: 382.221

Primary ExaminerWendell E. Burns Attorney, Agent, or Firm-Sughrue, Rothwell, Mion, Zinn & Macpeak [30] Foreign Application Priority Data July 25, 1972 June 6, 1973 France 72.27465 ABSTRACT A volumetric machine of the barrel of axial piston C c n a r F 6 0 2A6 5 4 757 nnAR 03 0 8 MW 40B, 7 A 2 00 5 (m y mluz m mmh MC .r. "3 "H "MS L C Umn N Hm-n 55 [56] References Cited tionary two-nappe frustrum of cone angularly integral UNITED STATES PATENTS with the frame of the machine. The two-nappe frustrums of cone have as their common generatrix the bisectrix of the obtuse angle defined by the axis of the machine and the axis of the swash-plate.

123/58 X 21 Claims, 9 Drawing Figures 790,374 5/1905 Maxwell...................,...,. 1,255,973 2/1918 A1mcn...... 1,300,098 4/1919 Almen 3.333.577 8/1967 Mongitorc PATENIEU AUGZSIQYS 3. 90 1 D93 sum 1 OF 8 PATENTEU mszsisrs SHEET S []F 8 PATENTEB wezsms SHEET 7 s 1975 AUGZ NTED FATE AXIAL PISTON MACHINE The present invention relates to a motion transforming mechanism applicable to engines or compressors having pistons, which are usually called axial or barrel engines.

Such engines or compressors are constituted by cylinders, the axes of which are substantially parallel, and equidistant to each other and about a central axis. The axes of the cylinders are substantially parallel to the central axis, or converge slightly towards the latter.

In such engines or compressors, the reciprocating rectilinear motion of the pistons must be converted into a rotary motion of the central shaft, or vice versa.

Such conversion is particularly difficult to achieve while obtaining a good performance, and numerous solutions have been proposed.

Certain solutions include an inclined disk fixed on the central shaft and rotating together therewith. This results in substantial frictions, since the peripheral speed of the disk is high.

The solutions which use cams result in high frictions as well.

Other known solutions include a pivoting swash-plate combined with a Z-shaft which acts as a crankshaft. In this case, the relative speeds are lower, but high stresses occur. On the other hand, if the shaft is symmetrical and the pivot is imaginary, it is difficult to control the motion of the swash-plate. Lastly, if the pivot does actually exist, it is usually constituted by a sphere, the diameter of which is bound to be great, or by a Cardan assembly which stands instead of it: in the first case there are again high frictions, and in both cases it is difficult to avoid some jamming conditions in certain positions of the cycle.

The main object of the invention is to provide a system of transformation having a pivoting swash-plate, wherein the stresses on the driving or driven crank are of the same order as in a conventional engine provided with piston, connecting-rod and crankshaft, while the friction of the real pivot is almost non-existent, any jamming condition being removed.

A volumetric machine according to the invention, for compressors or engines of the axial or barrel type, includes an inclined pivoting swash-plate, and is characterized in that the pivoting swash-plate drives the crank of a driving or driven shaft, the pivoting of said swashplate being defined by a two-nappe frustum of cone integral with the swash-plate and rolling, without sliding, on a stationary two-nappe frustum of cone angularly integral with the frame of the machine, the twoctwonappe frustums of cone having as their common generatrix the bisectrix of the obtuse angle defined by the axis of the machine and the axis of the swash-plate.

According to another feature of the invention, the four frustums of cone coupled by twos are each split up into a conical gear for rotative positioning, the pitch cone of which is the cone concerned, on the one hand, and a frustum of cone for the bearing and the positioning of the apex, with an apex angle definitely smaller than that ofthe cone concerned, on the other hand, the surface ofsaid bearing frustum of cone projecting beyond either side of the frustum of cone concerned.

According to an additional feature of the invention, the two fixed elements disposed coaxially and held fast in the frame of the machine, carry each a positioning gear for the rotation and a bearing frustum of cone with a smooth surface and an acute apex angle.

These two fixed elements can be adjusted:

on the one hand, in rotation with respect to each other, so as to cancel the play of the gears, and even create some rotation pres-stress,

on the other hand, in translation with respect to each other, so as to cancel the play of the bearings on the smooth cones, it being even possible to use this action to create some bearing prestress. Lastly, the assembly of the two coaxial elements fixed in rotation can be moved and adjusted in position with respect to the fixed frame of the machine, which allows varying the rate of compression of each piston in the cylinder thereof, the strokes of the pistons remaining, besides, constant, as defined by the angle of inclination of the pivoting swash-plate.

The accompanying drawing, which is given by way of non-limiting example, will enable the features of the invention to be more clearly understood.

FIG. 1 is a diagram illustrating the principle of the kinematics of a volumetric machine according to the invention.

FIG. 2 shows the arrangement of the cones which roll on each other without sliding.

FIG. 3 is an axial section showing the principle of an embodiment of the machine.

FIG. 4 is an axial section of the machine along line IVIV of FIG. 5.

FIG. 5 is a transverse section along line VV of FIG. 4.

FIG. 6 is a transverse section along line VIVI of FIG. 41

FIG. 7 is a longitudinal section of the piston, connecting-rod, connecting-rod linking, swash-plate, and pivot assembly when the piston lies at its uppermost dead point.

FIG. 8 shows the path of the centre of the connecting-rod/swashplate connection, as projected onto a transverse plane.

FIG. 9 corresponds to FIG. 7 when the piston lies at its lowermost dead point.

FIG. 1 illustratesthe principle of the kinematics of the pivoting of an axial machine according to the invention.

Two axes xx and yy' intersect at a point S and define to ether an angle 0:. The bisectrix ASB of the angles xSy and TXy, contained in the plane of the two straight lines, defines the following equal angles:

lf now (FIG. 2) the straight line AB rotates in the space about the axis xx, said line generates a cone with two nappes ASA and BSB, the apex half-angle of which is 01/2).

In the same way, if the straight line rotates about the axis yy, it generates another cone with two nappes ASA and BSB", identical with the first cone and having the same apex half-angle.

The two cones considered are tangent to each other along their common generatrix AB (which is always in the plane of xx-yy). The nappe ASA of the cone formed about xx is tangent to the nappe ASA" of the cone forme about yy along the half-straight line SA, and the nappe BSB of the cone formed about xx is tangent to the nappe 858 of the cone formed about yy along the half-straight line SB.

If the two conical surfaces are rotated about their respective axes xx and yy with the same angular speed to, they will roll on each other without sliding, as the contact between them always takes place along the common generatrix ASB which remains stationary in the space (always in the plane xx-yy).

Through a conventional kinematic transformation, by adding the speed (-1) about the axis xx, the cone ASA, BSB becomes stationary, and the axis yy rotates about xx at the speed (cu), while describing a cone, the apex half-angle of which is a. The generatrix of contact ASB rotates likewise together with the plane xx-yy about xx at the speed (w). This means that the cone ASA rolls on the stationary cone ASA without sliding, just as the nappe BSB rolls on the stationary nappe BSB without sliding. Of course, we are talk ing about immaterial geometrical surfaces, as the surfaces which are not conjugated interfere.

A first feature of the invention is to use this kinematic arrangement to obtain the frictionless pivot for the swash-plate intended for transforming the motion of a barrel device. The barrel defines cylinders, not shown, within each of which a piston slides, said piston being connected to the swash-plate 5 by a connecting-rod l (FIG. 3

A second feature of the invention is to remove the interferences of those surfaces which are not conjugated, so as to be able to materialize all the useful surfaces. To this end, said surfaces are truncated at the suitable locations, so that only frusto-conical surfaces remain (FIG. 3).

The stationary nappe ASA is limited by the two circles cc and dd, traces of two cylinders having xx as axis. Said nappe ASA defines thus a material solid limited by the inner and outer cylindrical surfaces of the annulus and by the frustum of cone cd-cd. cd-cd.

The second stationary nappe BSB is likewise limited to the frustum of cone ef-ef defining a material solid together with the cylindrical surfaces ee andff having xx as axis.

The frustum of cone cd is carried by the plate 1 and the column 2, which cannot rotate and are temporarily held fast as regards translation. The frustum of cone ef is carried by the plate 3 and the column 4 concentric with the column 2.

The first rolling nappe ASA", conjugate of the stationary nappe ASA, is limited to the frustum of cone glz defining a material solid together with the cylindrical surfaces gg and I111 having yy as axis (FIG. 3).

The second rolling nappe BSB, conjugate of the stationary nappe B88, is likewise limited to the frustum of cone jl defining thus a material solid together with the cylindrical surfaces jj and I] having yy as axis.

The two frustums of cone gh and jl, which have yy as axis, are carried by the piece or swash-plate 5, which is concentric therewith. The piece 5 is completed by the plate 6, the latter carrying a crankpin 7 which cooperates with the crank 8 of the driving or driven shaft 9. One of the two pieces 5 or 6, say, 6, has a number of arms which is equal to the number of driving or driven cylinders. Each arm Carries a joint 0, which can be spherical, which joint cooperates with the corresponding connectingrod 10.

The invention is characterized in the third place by the combination of the means (described hereinafter) used for constantly maintaining the coincidence at S of the apices of the two two-nappe cones, and preventing, on the other hand, said two cones from sliding on each other, whatever may by the loads and inertias generated in the system.

The invention is characterized in the fourth place by the combination of the means (described hereinafter) used for cancelling all the plays of the contacting rolling surfaces, and even maintaining some initial prestress between said surfaces.

A fifth feature of the invention is the combination of the means (described hereinafter) used for allowing the whole assembly illustrated in FIG. 3 to move axially along xx with respect to the fixed supporting frame and the cylinders (not shown), the axes of which are parallel, or substantially parallel to xx. This feature enables varying the volumetric ratio of the barrel engine considered according to a principle known per se either voluntarily, or automatically, as a function of the load, the ambient temperature, or the nature of the fuel. I

A sixth feature of the invention is the limitation of the driving or driven crankshaft to the shaft 9 and the crank 8. In particular, any central extension along xx, which would pass through the mechanisms corresponding to the preceding features, is excluded. For driving a flywheel and controlling the valve timing in a four stroke motor, we use here a lateral shaft 56 parallel to xx and running preferably at half-speed with respect to the shaft 9. Said shaft 56 receives its motion through spur gears on the shaft 9, preferably between the two bearings 22 and 23. It passes between the branches of the star and between the cylinders (FIG. 4). This shaft 56, which terminates above the cylinderhead of the engine, carries the earns 58 required for ensuring the valve timing in a four stroke engine, whether the number of cylinders is even or odd (while the valve timing through a central shaft would require an odd number of cylinders).

Said shaft 56 carries also the gears required for driving a short central shaft 61 carrying the flywheel 63, which runs at the speed of the engine, and constituting at the same time the axis of a rotor 66 for a mixer or a compressor.

The machine illustrated in FIG. 4 materializes more completely the diagrammatic FIG. 3.

The frustoconical surface gh (FIG. 3) is replaced by a conical gear 11 having the same apex S, and by a smooth frustum of cone 12 which has its apex S on yy and extends beyond either side of the imaginary surface of the frustum of cone g/z.

The smooth frustum of cone 12 (angle different from that of the toothed cone 1]) is preferably interior with respect to the conical gear 11, but it could be exterior with respect thereto. These two elements are carried by the swash-plate 5 and fixed thereon by means which are not shown.

The frustoconical surface ed (FIG. 3) is likewise replaced by a conical gear 13 having the same apex S, and by a smooth frustum of cone 14 which has its apex S on .rx' and extends beyond either side of the imaginary surface of the frustum of cone cd. These two elements are carried by the column 2 and rotatively blocked with respect thereto by the key 15. The two conical gears 1 1 and 13 mesh with each other, and have the same numbers of teeth. The smooth frustums of cone l2 and 14 have always a common generatrix along 8'8 and, although their apex half-angles differ by a, they have equal diameters at the level of their respective intersections with the frustums of cone gh and cd.

The frustoconical surface jl is likewise replaced by a conical gear 16 having the same apex S, and by a smooth frustum of cone 17 which has its apex S' on yy and extends beyond either'side of the imaginary surface of the cone jl. In FIG. 4, the gear 16 is exterior with respect to the frustum of cone 17, but the opposite position is equivalent as far as the invention is concerned. These two elements are carried by the swashplate 5 outside the cylinder surrounding the preceding system, and are secured to said plate by means which are not shown.

The frustoconical surface ef of FIG. 3 is likewise replaced by a conical gear having the same'apex S, and by a smooth frustum of cone 19, which has its apex S on xx and extends beyond either side of the imaginary surface of the frustum of cone ef. These two elements are carried by the plate 3 and by the column 4 concentrical with the column 2. They are fixed to said plate 3 by means which are not shown. The two conical gears 16 and 18 mesh .with each other and have the same number of teeth. The smooth frustums of cone l7 and 19 have always a common generatrix along 8 S and, although their apex half-angles differ by a, they have equal diameters at the level of their respective intersections with the frustums of cone jl and ef.

The cylindrical portion of the swash-plate 5 is closed by the plate 6 which carries the crankpin 7. This crank-' pin carries a bearing 20 axially xx locked by the nut 21. The bearing 20 is housed in the'crank 8, which rotates about the driving or driven shaft 9, the latter being carried by the bronze bushes or the rolle' r or needle bearings 22 and 23 in a manner such that it is capable of sliding lengthwise alon'g'xx.

The bearing 20 is illustrated as'a self-aligning roller bearing. lt might be replaced by a transverse double row ball bearing mounted in a spherical bush, or by two oppositely disposed tapered roller bearings mounted in a spherical sleeve. The p'ositionof the' centre D of the bearing on the crankpin 7 can be determined by washers 24.

At this point of the description, and assuming temporarily that the bearing 20 is duly a self-aligning roller angle at which SS stands to the virtual trajectory of pertaining to the swash-plate 5 along the generatrix AB, with respect to the imaginary frustums of cone cd and ef pertaining to the fixed gear. They ensure thus the permanent coincidence at S of the apices of the two two-nappe cones. v

It can also be seen thatthe conical pairs 11-13 and 1 6-8 define by their meshings two common points of the generatrix AB and ensure that the two two-nappe cones rotate on each other without sliding.

The assembly of the two columns 2 and 4 iscentred along xx and by the cylindrical supports 25 and 26 which serve as supports to the bending reactions. These two columns are keyed against relative rotation by the tenons 27 of the column 4, the tenon 28 of the column 2, the screws 29 and the lock-nuts 30 ofthe latter.

This differential keying allows cancelling the plays of the two pairs of gears 11-13 and 16-18, and even giving them eventually some initial pre-stress by relying on the torsional elasticity of the two columns.

The general keying against rotation of the assembly of the two columns with respect to the fixed frame is obtained through the tenons 31 on the column 4, the tenon 32 on the frame 33, the screws 34 and the locknuts 35 thereof. The frame 33 receives thus the reaction torque transmitted by the gears.

The two colums 2 and 4 are axially keyed to. each other by two screws 36, the locking means of which are not shown. Tightening the screws 36 causes the lifting of the column z alongg, and the lowering of the column 4 along xx. Through the agency of the, pairs of smooth cones 12-14 and 17-19, this would tend to reduce the angle a, but this is prevented by the bearing 20 and the crank 8. This tightening results thus in cancelling the plays of the smooth cones 12-14 and 17-19 and the plays of the bearings 20, 22 and 23 simultaneously, and even xx in giving to all said rolling surfaces a certain initial pre-stress by using the extension, compression, bending and torsional elasticity of all the parts of the system. v

The axial positioning of the assembly of the umns along xx is obtained as follows: I

The column, 4 (that is, from theforegoing, the assembly of 'the two columns) bears on a central spring 37.

adjustment, as they allow readily varying the flexibility of the spring 37, and, as will be seen hereinafter, they are advantageous for the operation too.

Said spring 33 bears on a crown 38 screwed frame 33 by means of the thread 39. The crown 38 is adapted to be rotated by a concentric gear 40, a pinion 41, a spindle 42, and a control means 43 provided with a locating means 44. The control and the locating may At rest, the spring 37 pushes thewhole movable as sembly upwards against a stop 45 carried by the cover 46 connected to the frame 33. It will be noted that the angular keying of the assembly of the movable gear obtained by means of the screws 34 has a slightplay. which allows the slight axial movement of said gear'during the operation under the effect of the equilibriumof the 1.

two col- I in the. y

forces brought into action against the spring 37. In a mass-production line, such keying by the screws 34 can be replaced by a sliding keying or by flutes.

Oil under moderate pressure from the lubricating pump is introduced through the nozzle 67 into the enclosure constituted by the frame 33, the cover 46 and the plate 3. Said oil can only escape by the play of the cylindrical centring means 25 and through the calibrated jets 68, it being understood that between the nozzle 67 and the lubricating pump there is a nonreturn valve which is not shown.

To receive or generate the reciprocating motions of the pistons, the swash-plate is provided with a number of arms 47 which is equal to the number of pistons brought into action. This number can be any number from one (inclusive).

In the scope of the invention, the engine may be a four-stroke or two-stroke internal-combustion engine, a controlled ignition engine, a compression ignition en gine, a steam engine, or a hot air engine (Stirlings cycle).

We are taking here as an example a five cylinder, four stroke engine.

The points of articulation O of the connecting-rods on the arms 47 of the swash-plate are all equidistant from S and selected so as to lie substantially along the axes of the engine cylinders. These points might have been disposed within the plane Zz perpendicular to the axis yy at S, in order to obtain a left trajectory of projection in the shape of a symmetrical figure eight, with a minimum amplitude of the movement of O with respect to the axes of the cylinders (FIG. 3). It may be preferable, as shown in FIG. 4, to select 0 slightly below the plane 22, so as to reduce the upper loop of said figure eight to a minimum, and cancel the lateral movement of O, hence the angular movement of the connecting-rods 10 at the time the pressure stresses in the cylinders are maximum, almost completely. This takes place to the prejudice of the lower loop of the figure eight, which becomes greater (but there is no more pressure).

Of course, ball and socket joints such as those shown in FIG. 3 can be used at O with spherical-end connecting rods. The relative sliding in a joint of this kind is slightly higher than that which occurs in a conventional piston pin. This is the reason why the invention proposes, as a modification, a type of joint which is substantially frictionless, and, therefore, more homogeneous with the pivot just described.

The joint proposed as a modification is detailed in FIGS. 7, 8, and 9, wherein the pivot already shown in FIG. 4 is reproduced as a more developed embodiment.

In these Figures we find again the centre S of the pivot at the intersection of the axis xx of the machine and the axis yy of the swash-plate, the plate 1 which is here in the shape of a nut, the column 2, the plate 3, and the sleeve 4. The swash-plate comprises an upper portion 5, and a lower portion 6 which ends in the crankpin 7. The upper portion 5 of the swash-plate carries the gear 11 and the smooth concave cone 12, which are respectively conjugated with the gear 13 and the smooth convex cone 14 carried by the column 2 and the plate 1, respectively. The flutes 15 hold the gear 13 during the rotation. The lower portion 6 of the swash-plate carries the gear 16 and the smooth concave cone 17, which are respectively conjugated with the gear 18 and the smooth convex cone 19. The positions thereof are inverted with respect to those shown in FIG. 4.

One of the five arms 47 (for a five cylinder machine) fixed to the swash-plate 6 is shown as carrying a connecting-rod couplin having a theoretical centre O.

The axis tr of the corresponding cylinder is parallel to xx, and along said axis the point of articulation of the connecting-rod to the piston is at P. The axis of the connecting-rod is P0.

The point O is selected on the swash-plate in the trace plan 12 perpendicular to xx at the point S. With the motion of the swash-plate, said point O describes a trajectory the trace of which inis an arc of a circle 0 0"O such that O S O O S O a, subtended by a subtense 00 which intersects at I the trace nn of the transverse plane of the machine which passes through S, in a manner such that OI IO. In projection on the plane nn, the trace of said trajectory is a circle (FIG. 8) having a diameter equal to the deflection distance IO", and a centre U such that U] UO.

, and

(l+cos'a) =50 2 In order the axis tr passes through U, it is thus necessary that its distance from xx should have a value SO l cos 01/2).

Under such conditions, the axis P0 of the connecting-rod describes a conoid about tt, said conoid having an apex half-angle B.

It will be assumed first that the length PO is very great, which amounts to reducing B to zero.

In the pivot of the swash-plate, the bisectrix AB passing through S and being, as already seen, the common generatrix of the basic pitch cones passes through the contact segment of the smooth cones l2 and 14 and the contact segment of the cones l9 and 17 while defining large angles with said segments, which prevents the swash-plate from rotating in the plane of the figure, about the ball crankpin 7.

If a parallel KK to AB and a parallel OV to yy are drawn through 0, we find the same situation at O as at S. The convex cone mounted on the rod 81, which has OV as axis, is fixed to the swash-plate by the arm 47. The conjugated concave cone 82 is cut from a socket 83 fitted on the smooth end 84 of the connecting-rod 93. Said socket 83 bears, through an adjusting shim 92, on the piece 85 which is screwed on the connecting-rod and locked by the lock-nut 86. A socket 87 concentric with the socket 83 is fixed on the piece 85 and carries a concave cone 88 which is conjugated with the convex cone 89 cut from the socket 90, the latter being concentric with the rod 81 and being held in position together with said rod on the arm 47 by the nut 91.

The axis KK passes through the contact generatrix of the conjugated frustums of cone 88 and 89 and through the contact generatrix of the conjugated frustums of cone 80 and 82, while defining large angles with said generatrices.

It is clear that these two oppositely mounted couples of frustums of cone define the point O, and the substantial stresses resulting from the loads and inertias will pass through said generatrices with a low Hertzian pressure and under rolling conditions practically free from any sliding.

Taking into account the equality of the mean diameters in each couple, the connecting-rod will not rotate about its axis during the motion of the swash-plate, nor will the pivot supporting column 2 rotate. But if it is found advantageous (and it is, indeed) that the connecting rod should rotate on its axis, it is easy to make it do so by shifting both the contact segment of 89 towards the apex of its cone and the contact segment of 80 towards the apex of its cone. By shifting both of them in the opposite direction, the connecting-rod is caused to turn on itself in the reverse direction with respect to what has been observed previously.

All this implies that the value of the angle [3 is zero. In actual fact, the connecting-rod is rather short, so that the value of B may be near 2.

A pinion 54 is keyed on the shaft 9 of the engine, anf follows the possible axial movement of said shaft. A toothed wheel 55 meshes with said pinion, and has preferably a diameter twice that of said pinion, although this is not absolutely necessary according to the invention. Said wheel is keyed on the shaft 56, which has its axis parallel to xx and has no axial movement. To prevent the relative angular keying between the shaft 9 and the shaft 56 from varying, the couple of gears thus defined has straight teeth. The shaft 56 passes through two arms 47 of the swash-plate (FIG. without hampering the movement of the latter. lt passes likewise between two adjacent cylinders. Said shaft 56 controls, through a pair of helical pinions 57, the oil pump, the fuel pump, and the ignition distributor in a controlled ignition engine (these three elements are not shown). The shaft 56 is also able to control the injection pump of a compression ignition motor through means which are also conventional.

The shaft 56 emerges from the group of cylinders to enter the cylinderhead, and, by means of cams 58 diagrammatically illustrated, it ensures in a conventional way the valve timing of a four stroke engine. Lastly, the

end of the shaft 56 is provided with a wheel 59, the diameter of which is equal to that of the wheel 55, said wheel 59 meshing with a pinion 60, the diameter of which is equal to that of the pinion 55. Said pinion 60 is mounted on a shaft 61 coaxial with the shaft 9, running at the same speed and in the same direction as the latter.fandniaintaining the keying desired. The teeth of the couple of gears 59-60 may be helical. Two

' flywheels 62 and 63 are mounted on the shafts 9 and 61, respectively, and have unbalancing means 64 and 65 opposed by 180 to compensate for the primary torques of inertia'Thc shaft 61 carries a rotor 66 which ensures the distribution of the fuel mix in the controlled ignition engine, while creating a certain overfeeding in every case.

Of course, ihefl'ywhe'el 62 is used for controlling the transmission through a clutch (not shown), in spite of its possible slight axial displacement.

1n the above description, the kinematic operation of the swashplate, the pivot thereof, the articulation thereof to the connecting-rods, and the transformation of the motion between the connecting-rods and the driving shaft 9, is already quite visible. The feasibility of the axial motion of the whole of the arrangement is likewise already .very much underlined. The following remarks will complete the picture of the operation:

It is assumed that the arm 47 (l) is in its uppermost position, that is, the piston corresponding to 01 is at the uppermost dead point, and 01 is in the plane xED of the crank. The stress resulting from the explosion is borne by the parallel to the axis xx at 01. The inertia applied to the piston and connecting-rod mass is deducted from F1; the most unfavourable instance is that of a slow motion, when said inertia is almost zero and F1 is maximum. If it is desired that the axial stress on the bearing 20 should be zero, or near zero, the reaction F2 of the crank is brought to bear on the extension of ED, the reaction F3 of the cone 14 on the cone 12 should be perpendicular to the common generatrix S'S at the point where the latter intersects the generatrix ASB. The angle Ss and A88 is thus selected at best. As previously noted, there is no sliding Whatever at this point of the generatrix common to the cones l2 and 14, and, therefore, no friction. On the other hand, there is a slight friction on said common generatrix on either side of ASB. The bearing 20 works exactly in the same way as a crankpin. The conical bearing 12-14 works much better than a conventional bearing, owing to the low l-lertzian pressures. The forces F 1, F2, F3 remain proportional.

The cones 17 and 19 do not produce any reaction: they would sooner tend to lift, so that a pre-stress is advantageous. In the vicinity of the lowermost dead point the pressure stresses on the arms 47 (3) and 47 (4) are very low, and are disregarded.

When the motion is quick, the inertias resulting from the masses of the pistons, connecting-rods, and swashplate become important. They are maximum in the uppermost position 01. when the cylinders are in even number, the inertias of two opposed pistons balance each other, and the resultant thereof is zero along the axis xx. When the cylinders are in odd number, as in the example selected, balancing masses (not shown) may be disposed in the hollows of the swashplate, at points such as 69 so as to obtain a resultant equal to zero.

In every case thereis an important inertia torque on the swashplate, which torque is transmitted to the frame 33 by the contact of the cones 17 and 19 along their contact line SS"', on the one hand, and through the crankpin 7 and the crank 8, on the other hand. Said inertia torque is balanced by an opposing torque created by the rotating masses 64 and 65 of the flywheels.

In a position of 01 different from the uppermost position, as, for instance, in the position 02 (FIG. 5), the force F2 applied to the crankpin 20 (or D) creates the instantaneous torque; the reaction F3 is received by the reactions F4 and F5 of the teeth of the pairs of conical gears, respectively F4 on the pair 11-13, and F5 on the pair 16-18. The values of F4 and F5 are varying depending on the position of 02, and cancel each other when 02 is in the uppermost position. The corresponding torques are received by the columns 4 and 2, and transmitted to the frame 33 by the stops 28 and 32. The instantaneous variations in these couples of gears are such that they demonstrate how much the taking up of play previously described, and even the slight prestress, are advantageous.

1n thecase of a compressor, a steam engine, or a hot air engine, the axial displacement of the system is only moderately advantageous, and it is preferred then to replace the spring 37 by shims.

On the contrary, in the case of a two stroke or four stroke, controlled ignition or compression ignition internal combustion engine, said axial displacement is highly important, since it allows varying the compression ratio while the engine is running.

In the example selected, it will be noted that at rest the whole movable assembly of the columns 2 and 4 is pressed against the stop 45 by the spring 37, which gives the engine a maximum compression ratio under the starting conditions. when the engine is running, the mean thrust in the direction xx is the stronger as the effective mean pressure (E.M.P.) in the cylinders is stronger. The stronger the mean thrust, the more the spring 37 is compressed, the more the pivot S is moved away from the stop 45, the more the end of stroke position of the pistons is far from the plane of the cylinderhead, the bigger the volume of the chamber of combustion, and the more the compression ratio decreases, since the stroke is constant. The stiffness of the spring 37 may be selected at will. For instance, for a controlled ignition engine, a compression ratio of 7/1 at full load (which reduces the nitrogen oxides), and of 14/1 at the start (which ensures a good starting) may be selected, with values which vary continuously between l4/l and 7/1 for all the values of the E.M.P. (which, at reduced loads, ensures both complete combustions without any carbon monoxide or unburnt matters, and a thermal efficiency as good as at full loads). As the mechanical efficiency of the assembly described is excellent, the pollution and the mean specific consumption are very reduced.

Of course, the H68. 14 and 7 have been quoted in order to make the reasoning easier, the growth of the compression ratio being experimentally defined by the limit of detonation in every load condition and for every type of engine.

As the instantaneous thrust of the pistons on the swash-plate is periodically varying, and the movable assembly must not begin to vibrate, the dampening is carried out by the lubrication oil passing through the enclosure defined by the piston 3 and the frame 33. The selection of the size of the outlet holes 68 allows adjusting the value of such dampening.

While moving axially, the movable assembly carries along the crank 8 and the driving shaft 9, which slides in the bearings 22 and 23. This movement takes part too in the dampening of the movable assembly through the inertia of the flywheel 62 and the friction of the gearings 54 and 55. On the other hand, this movement which amounts to a few millimetres is not a seri ous inconvenience for the transmission of power.

Displacing the bearing surface 38 of the spring 37 by means of an exterior manual drive 40-41-42-43 allows modifying the average compression ratio one way or the other. This allows using fuels having very different octane numbers and volatility. Thus, in a controlled ignition engine, increasing mean ratios may be used for leadless gasoline, high-grade gasoline, methanol, and even for slightly hydrated methanol. In a compression ignition engine, different adjustments will be ensured for gas, oil and gasoline.

Said drive 40-41-42-43 may also be brought under the control of the instruments measuring the atmospheric conditions, and, in particular. the thermometer.

I claim:

1. A volumetric machine of the so-called barrel or axial piston type, including pistons which rest on an oblique pivoting swash-plate, characterized in that the pivoting swash-plate drives the crank of a driving or driven shaft, the pivoting of said swash-plate being defined by a two-nappe frustum of cone integral with the swash-plate and rolling, without sliding, on a stationary two-nappe frustum of cone angularly integral with the frame of the machine, the two two-nappe frustums of cone having as their common generatrix the bisectrix of the obtuse angle defined by the axis of the machine and the axis of the swash-plate.

2. A volumetric machine according to claim 1, characterized in that the four frustums of cone coupled by twos are each split up into a conical gear for rotative positioning, the pitch cone of which is the cone considered, and a frustum of cone for the bearing and positioning of the apex, with an apex angle definitely smaller than that of the cone considered, the surface of said bearing frustum of cone extending beyond either side of the frustum of cone considered.

3. A volumetric machine according to claim 2, char acterized in that the stationary two-nappe frustrum of cone is comprised of two elements ea h carrying gearing for rotation positioning and an acute bearing frustum of cone, while they are adapted to be rotatingly ad justed with respect to each other so as to remove the play of the gearings, and even create a certain rotation pre-stress, and adjusted, besides, in translation with respect to each other so as to remove the play of the bear ings, and even create a certain bearing pre-stress.

4. A volumetric machine according to claim 3 characterized in that the assembly of the two elements coaxial to the frame of the machine is carried by a spring which allow a slight axial displacement thereof, which leads to the same displacement of the swash-plate and the driving shaft, this displacement being created by the value of the mean axial thrust of the pistons, hence the value of the effective mean pressure on the pistons,

and producing thus compression chamber heights,

hence volumes, the greater as the effective mean pressure is stronger, and, therefore, all the lower compression ratios.

5. A volumetric machine according to claim 4, characterized in that the axial displacement is dampened by the lubrication oil trapped between the frame and the piston integral with the movable assembly, which oil goes in through a nozzleand a non-return valve, and comes out through calibrated jets to lubricate the mechanisms, the calibres of the jets allowing to adjust the amount of dampening.

6. A volumetric machine according to claim 4, characterized in that the base of the bearing spring is adapted to be axially displaced by the rotation of a nut which is remotely controlled from the outside, so as to modify the mean compression ratio ofthe engine, while said drive for the nut may be manual to adapt said ratio I to various fuels having different octane numbers or volatilities, or brought under the control of a thermoinctric device to adapt said ratio to the atmospheric or starting conditions.

1 7. A volumetric machine according to claim 1, characterized in that it includes a flywheel opposed to the driving or driven flywheel and running at the same speed as the latter while carrying masses for balancing the inertia torque. said balancing flywheel being con-- trolled by an intermediate shaft parallel to the driving shaft and running at any speed, while being connected to the two shafts of the two flywheels by pairs of gear- 13 ings having identical gear ratios, said intermediate shaft passing through the gap between two arms of the swash-plate and the gap between the two corresponding cylinders.

8. A barrel or axial piston volumetric machine according to claim 1, characterized in that the connection of each piston P to the periphery 47 of the swash-plate is ensured by two pairs of smooth cones (82 and 88 on the rod 93 of the piston P, and 80 and 89 on the swashplate 47) which roll on each other and are mounted in opposition, so that they ensure both the accurate positioning of the theoretical point of articulation O and the transmission through rolling of the all the load and inertia stresses.

9. A volumetric machine according to claim 8, characterized in that the two segments of the contact generatrices of the two pairs of frustums of cone straddle the isospeed straight line KK', bisectrix of the angle a of the two basic cones 80, 82 or 88, 89 and defining an angle (90 11/2) with the axis of the cylinder, at being the angle of the axis yy of the swash-plate to the axis xx of the cylinder.

10. A volumetric machine according to claim 8, characterized in that the male cones 80 and 89 are both fixed on the swash-plate 47, while the female cones 82 and 88 are both fixed on the connecting rod 93 of the piston P.

11. A volumetric machine according to claim 8, characterized in that the two pairs of smooth cones include: one female conical rolling surface 82 integral with the rod 93 and converging towards the piston P;

one male conical rolling surface 80 integral with the swash-plate 47 and converging towards the piston P, while rolling inside the face 82, with which it is constantly in contact through one and only generatnx; one female conical rolling surface 88 integral with the rod 93 and diverging towards the piston P;

one male conical rolling surface 89 integral with the swash-plate 47 and diverging towards the piston P, while rollingv inside the face 88, with which it is constantly in contact through one and only generatrix.

12. A volumetric machine according to claim 8, characterized in that the two female cones 82 and 88 are fixed to the connecting-rod 93 of the piston P, while the male cones 80 and 89 are both fixed to the swash-plate 47.

13. A volumetric machine according to claim 11, characterized in that the female conical rolling surfaces 82 and 88 are coaxial, and axially off-set with respect to each other, the face 82 being nearer to the piston P as the face 88, so as to define between them a gap in which the two conical faces and 89 of the swashplate 47 are housed in opposition.

14. A volumetric machine according to claim 11,

characterized in that the annular frustoconical traclc' defined by the rolling face 82 has an outer diameter lower than the inner diameter of the annular frustoconical track defined by the rolling face 88, which allows housing a socket between said two tracks, said socket being integral with the swash-plate 47.

15. A volumetric machine according to claim 9, characterized in that the isospeed straight line KK' defines with the generatrix of contact of the conjugated cones 88 and 89 an angle greater than 20, and thus greater than the jamming angle of the mechanism.

16. A volumetric machine according to claim 8, characterized in that the mean rolling diameters of each pair of cones 80, 82 and 88, 89 are equal, so that the connecting-rod 93 does not turn on itself.

17. A volumetric machine according to claim 8, characterized in that the mean rolling diameters of each pair of cones 80. 82 and 88, 89 are unequal, so that the connecting-rod 93 turns slowly on itself.

18. A volumetric machine according to claim 8, characterized in that the angle (angle of the actual axis P0 of the rod 81 with respect to the theoretical axis P0" of the cylinder) is lower than, or equal to 3.

19. A volumetric machine according to claim 8, characterized in that each piston P is rigidly fixed to its connecting rod 93 which is coaxial thereto, the bearing of the piston P on the cylinder 95 being spherical as well as that of the single compression ring 97, while an oil scraper-ring 99 is carried by a counter-piston which slides within the cylinder 95 and receives, through a spherical joint, the rear face of the oscillating piston P.

20. A volumetric machine according to claim 8, characterized in that each piston P is rigidly fixed to its connecting rod 93 which is axial thereto, the bearing of the piston P on the cylinder 95 being conical, while that of its compression ring 97 is spherical, an oil scraper-ring 99 being carried by a counter-piston 100 which slides within the cylinder 95 and receives, through a spherical joint, the rear face of the oscillating piston P.

21. A volumetric machine according to claim 20, characterized in that the frustoconical bearing of the piston P on the cylinder 95 has an apex half-angle equal tothe angle defined by the axis of the connecting-rod 93 with the axis tu of the cylinder 95. 

1. A volumetric machine of the so-called barrel or axial piston type, including pistons which rest on an oblique pivoting swashplate, characterized in that the pivoting swash-plate drives the crank of a driving or driven shaft, the pivoting of said swashplate being defined by a two-nappe frustum of cone integral with the swash-plate and rolling, without sliding, on a stationary two-nappe frustum of cone angularly integral with the frame of the machine, the two two-nappe frustums of cone having as their common generatrix the bisectrix of the obtuse angle defined by the axis of the machine and the axis of the swash-plate.
 2. A volumetric machine according to claim 1, characterized in that the four frustums of cone coupled by twos are each split up into a conical gear for rotative positioning, the pitch cone of which is the cone considered, and a frustum of cone for the bearing and positioning of the apex, with an apex angle definitely smaller than that of the cone considered, the surface of said bearing frustum of cone extending beyond either side of the frustum of cone considered.
 3. A volumetric machine according to claim 2, characterized in that the stationary two-nappe frustrum of cone is comprised of two elements each carrying gearing for rotation positioning and an acute bearing frustum of cone, while they are adapted to be rotatingly adjusted with respect to each other so as to remove the play of the gearings, and even create a certain rotation pre-stress, and adjusted, besides, in translation with respect to each other so as to remove the play of the bearings, and even create a certain bearing pre-stress.
 4. A volumetric machine according to claim 3 characterized in that the assembly of the two elements coaxial to the frame of the machine is carried by a spring which allow a slight axial displacement thereof, which leads to the same displacement of the swash-plate and the driving shaft, this displacement being created by the value of the mean axial thrust of the pistons, hence the value of the effective mean pressure on the pistons, and producing thus compression chamber heights, hence volumes, the greater as the effective mean pressure is stronger, and, therefore, all the lower compression ratios.
 5. A volumetric machine according to claim 4, characterized in that the axial displacement is dampened by the lubrication oil trapped between the frame and the piston integral with the movable assembly, which oil goes in through a nozzle and a non-return valve, and comes out through calibrated jets to lubricate the mechanisms, the calibres of the jets allowing to adjust the amount of dampening.
 6. A volumetric machine according to claim 4, characterized in that the base of the bearing spring is adapted to be axially displaced by the rotation of a nut which is remotely controlled from the outside, so as to modify the mean compression ratio of the engine, while said drive for the nut may be manual to adapt said ratio to various fuels having different octane numbers or volatilities, or brought under the control of a thermometric device to adapt said ratio to the atmospheric or starting conditions.
 7. A volumetric machine according to claim 1, characterized in that it includes a flywheel opposed to the driving or driven flywheel and running at the same speed as the latter while carrying masses for balancing the inertia torque, said balancing flywheel being controlled by an intermediate shaft parallel to the driving shaft and running at any speed, while being connected to the two shafts of the two flywheels by pairs of gearings having identical gear ratios, said intermediate shaft passing through the gap between two arms of the swash-plate and the gap between the two corresponding cylinders.
 8. A barrel or axial piston volumetric machine according to claim 1, characterized in that the connection of each piston P to the periphery 47 of the swash-plate is ensured by two pairs of smooth cones (82 and 88 on the rod 93 of tHe piston P, and 80 and 89 on the swash-plate 47) which roll on each other and are mounted in opposition, so that they ensure both the accurate positioning of the theoretical point of articulation O and the transmission - through rolling - of the all the load and inertia stresses.
 9. A volumetric machine according to claim 8, characterized in that the two segments of the contact generatrices of the two pairs of frustums of cone straddle the isospeed straight line KK'', bisectrix of the angle Alpha of the two basic cones 80, 82 or 88, 89 and defining an angle (90* - Alpha /2) with the axis of the cylinder, Alpha being the angle of the axis y''y of the swash-plate to the axis x''x of the cylinder.
 10. A volumetric machine according to claim 8, characterized in that the male cones 80 and 89 are both fixed on the swash-plate 47, while the female cones 82 and 88 are both fixed on the connecting rod 93 of the piston P.
 11. A volumetric machine according to claim 8, characterized in that the two pairs of smooth cones include: one female conical rolling surface 82 integral with the rod 93 and converging towards the piston P; one male conical rolling surface 80 integral with the swash-plate 47 and converging towards the piston P, while rolling inside the face 82, with which it is constantly in contact through one and only generatrix; one female conical rolling surface 88 integral with the rod 93 and diverging towards the piston P; one male conical rolling surface 89 integral with the swash-plate 47 and diverging towards the piston P, while rolling inside the face 88, with which it is constantly in contact through one and only generatrix.
 12. A volumetric machine according to claim 8, characterized in that the two female cones 82 and 88 are fixed to the connecting-rod 93 of the piston P, while the male cones 80 and 89 are both fixed to the swash-plate
 47. 13. A volumetric machine according to claim 11, characterized in that the female conical rolling surfaces 82 and 88 are coaxial, and axially off-set with respect to each other, the face 82 being nearer to the piston P as the face 88, so as to define between them a gap in which the two conical faces 80 and 89 of the swash-plate 47 are housed in opposition.
 14. A volumetric machine according to claim 11, characterized in that the annular frustoconical track defined by the rolling face 82 has an outer diameter lower than the inner diameter of the annular frustoconical track defined by the rolling face 88, which allows housing a socket 90 between said two tracks, said socket being integral with the swash-plate
 47. 15. A volumetric machine according to claim 9, characterized in that the isospeed straight line KK'' defines with the generatrix of contact of the conjugated cones 88 and 89 an angle greater than 20*, and thus greater than the jamming angle of the mechanism.
 16. A volumetric machine according to claim 8, characterized in that the mean rolling diameters of each pair of cones 80, 82 and 88, 89 are equal, so that the connecting-rod 93 does not turn on itself.
 17. A volumetric machine according to claim 8, characterized in that the mean rolling diameters of each pair of cones
 80. 82 and 88, 89 are unequal, so that the connecting-rod 93 turns slowly on itself.
 18. A volumetric machine according to claim 8, characterized in that the angle (angle of the actual axis PO'' of the rod 81 with respect to the theoretical axis PO'''' of the cylinder) is lower than, or equal to 3*.
 19. A volumetric machine according to claim 8, characterized in that each piston P is rigidly fixed to its connecting rod 93 which is coaxial thereto, the bearing of the piston P on the cylinder 95 being spherical as well as that of the single compression ring 97, while an oil scraper-ring 99 is carried by a counter-piston 100 which slides within the cylinder 95 and receives, through a spherical joinT, the rear face of the oscillating piston P.
 20. A volumetric machine according to claim 8, characterized in that each piston P is rigidly fixed to its connecting rod 93 which is axial thereto, the bearing of the piston P on the cylinder 95 being conical, while that of its compression ring 97 is spherical, an oil scraper-ring 99 being carried by a counter-piston 100 which slides within the cylinder 95 and receives, through a spherical joint, the rear face of the oscillating piston P.
 21. A volumetric machine according to claim 20, characterized in that the frustoconical bearing of the piston P on the cylinder 95 has an apex half-angle equal to the angle defined by the axis of the connecting-rod 93 with the axis tu of the cylinder
 95. 